Hello Ella, I too love to write but never finish anything. Is this a literary match made in heaven? Well, lets read your story and find out, as I'm trying to review everything I read! (Damn, that sounded creepy.)

-Firstly, this can get a bit confusing at times. Characters lack description. I therefore may have misread the situation: that, because she lacks a male heir, the mother can't keep the farm.

I can't help but think that a simpler response would be for the mother to just get remarried and have more kids than to make her child go through the whole charade. (This would also give her more manual labour at the fields; this is part of the reason why birth rates are higher in poorer countries, and in the middle ages.) In addition, pretending to be a boy in a poor medieval village, where houses were usually very small (little modesty), everyone knew each other, and gossip spread quickly would be pretty difficult. (Then we get to her having periods, growing breasts...) It wouldn't be impossible, but showing us some of the ways in which Erin hides her gender would be an interesting addition to the story. (Exactly when did she become a boy? Because a daughter dissapearing and being replaced with a son would become a talking point pretty quickly.)

-I'd have thought a practical farmer's girl, such as Erin, would know to bring food with her before setting off on a boat journey. I can accept her (just-she lives on the coast, and therefore possibly near people who know about boats) not knowing that an open rowing boat isn't great at ocean travel, but not bringing food is pretty odd. I similarly don't understand how you can accidentally pack a harness of plate armour (Erin seems to have noticed this.)

-In addition, if someone wears armour, that someone doesn't strike me as a 'peaceful man'. Even leaders who fight for the noblest reasons, but use violent means, aren't usually 'peaceful men'.

-Sometimes, you could also describe the action in a bit more detail. (How does Erin 'kill a shark' with a piece of armour? How does it feel? And so on.)

Still, this has promise, and an interesting premise. Good luck, and keep writing!